Legal uncertainties

It is well known that in any functional justice system there will be problems.  It is a sad truth that false positives are inversely correlated with false negatives.  Fewer of one will get you more of the other, and in any system with actual uncertainty there will be plenty of both.  A traditional approach has been:

It is better that ten guilty persons escape than that one innocent suffer

The modern approach has drifted more in the direction of public safety, but the general principle of there being an unpleasant trade-off remains intact. 

So the Amanda Knox case has been in the news and it is a perfect example of when these principles come into conflict.  What seems clear is that that there was at least one killer, Rudy Guede, who left a lot of forensic evidence (bloody handprint, for example).  So the real question is whether this was a group killing or the act of a lone killer. 

But here the evidence gets tough.  She clearly lied to the police, was convicted of this crime, and spent three years in prison for it.  Witnesses, of possibly dubious reliability, seem to contradict her story which isn't good but also doesn't prove much, either.  The evidence seems mixed, with the question of additional weapons needing to be raised to make the case work and the lack of a motive for Knox and Sollecito to work with a complete stranger is ambiguous.

The latest comments from the judge also worried me:

Judge Alessandro Nencini also suggested in an interview with Corriere della Sera published Saturday that the decision of Knox's ex-boyfriend and co-defendant, Raffaele Sollecito, not to testify may have worked against him.

"It's the defendant's right, but it certainly deprived the process of a voice," Nencini was quoted as saying. "He limited himself to spontaneous declarations. He said only what he wanted to say without letting himself be cross-examined." Knox did not appear at the trial, but sent a letter to the court saying she feared wrongful conviction.

This is getting awfully close to forcing testimony, which is a deadly game when open-ended questions can be asked, people are nervous, and perjury is a crime.  Or this:

"At the moment I can say that up until 8:15 of that evening, the kids had other plans, but they skipped them and an opportunity was created," Nencini was quoted as saying. "If Amanda had gone to work, probably we wouldn't be here."

Which I am hoping is a bad translation from Italian, or that it means that Kercher would still be alive and thus there would be no case. 

So obviously I am not an expert on this case nor have I followed it in great detail.  But I remain confused by why the prosecution isn't putting forth their best case.  As it is we have ambiguous DNA evidence (with the girls being housemates), another party clearly involved in the crime (at some level) with every reason to lie, and a lot of complex theories. 

So far, what I see, is pretty good evidence that Amanda lied to police and that she served time for that offence.  I am a little unclear why the better evidence isn't being presented publicly, as the public nature of criminal proceedings are a great way to inspire confidence in the justice system.  The courts appear to be very worried about false negatives in this case, and perhaps they should re-evaluate just what trade-offs they are willing to make.